1. Field of Invention
The technical scope of the present invention is that of deployment and drive devices for projectile fins, and in particular for control surfaces, i.e. fins able to pivot when in the deployed position, under the action of a piloting motor.
2. Description of Related Art
Control surfaces play a role in the piloting of a projectile but may also have a role to play in its stabilization, similarly to the control surfaces of a plane, since they are controlled in rotation by a motor piloted by an electronic system. The piloting of the projectile enables its trajectory to be corrected in flight thus compensating for any errors made in laying or orienting the projectile on a target after detecting such a target.
The main disadvantage of such control surfaces lies in that, to be effective, they must have large dimensions (the length of the control surface is usually around that of the calibre) thereby making it impossible to fire the projectile from a weapon of this calibre. Thus, over the past years, different fin and control surface deployment mechanisms have been developed for projectiles ranging from missiles, to rockets, or sub-projectiles on-board a large calibre spin-stabilized carrier shell. These mechanisms however remain cumbersome and heavy, thereby reducing the projectile's payload.
Projectiles are thus sought to be equipped with control surface deployment and orientation devices.
Thus, U.S. Pat. No. 6,446,906 describes a device to unblock and orient control surfaces, said orientation being ensured by two motors each acting on a pair of control surfaces.
Such a solution suffers from an incontestable drawback however. Indeed, the control surfaces are released by means of a pyrotechnic device, which, on the one hand takes up a certain volume thereby further reducing the payload able to be carried by the projectile, and on the other leaves a risk of accidental deployment of the control surfaces, namely during the handling phases of the projectile.
U.S. Pat. No. 6,186,443 also describes a deployment and drive device for the wing of an aircraft. Such a device is only adapted, however, to the deployment of one wing and not to the simultaneous deployment of several control surfaces. It may therefore not be adapted to projectiles without further reducing the space given over to the payload.
Patent application WO-02/18867 describes a control surface deployment device. This document namely proposes a device for the simultaneous deployment of control surfaces and then an individual orientation mechanism for each control surface, once again increasing the volume of the device.